The jury in the trial of Chris Huhne's ex-wife, Vicky Pryce, at Southwark crown court has been discharged after failing to reach a verdict on a charge of perverting the course of justice by taking speeding points for him.

Mr Justice Sweeney told the jury: "I have received your note which indicates that it is 'highly unlikely' that you are going to reach even a majority verdict. I am grateful for that.

"Against the background of the length of time that you have been in retirement already, I have decided therefore, and it is my decision one way or the other, that I must discharge you from any further deliberations.

"That means that your role in this case is now over."

Pryce will face a retrial. She showed little emotion as the judge discharged the jury, sitting with her chin in her hand.

Earlier, Sweeney had told the jury it could reach a majority verdict as he addressed 10 specific questions that the jury had asked him about the case. The panel of eight women and four men had been deliberating for almost 14 hours when the judge told them they could reach a verdict on which at least 10 of them could agree.

Sending them back out to continue their deliberations he said: "If for any reason one or more of you feel less than confident that you understand and are able to apply my directions of law, then it would be wholly wrong for any juror in that position to reach a verdict one way or the other."

Pryce, 60, an economist, had denied the charge on the grounds of marital coercion, telling the jury that Huhne, then an MEP for South East England, had pressured her to take his speeding points in 2003.

Huhne, 58, changed his plea to guilty on the first day of his trial on 4 February and resigned as MP for Eastleigh, sparking a byelection.

The one-time contender for the Liberal Democrat leadership had stepped down from the cabinet on being charged last year. He now awaits sentence and faces the prospect of jail.

The jury heard that the speeding points allegations first emerged in newspaper stories in May 2011, a year after Huhne left Pryce, his wife of 26 years, for a PR adviser, Carina Trimingham, 46. The prosecution claimed Pryce went to the newspapers with the story in revenge because she wanted to "nail" her former husband and destroy his career.

The prosecution said she had first tried to "peddle a false story" to the Mail on Sunday that a constituency aide had taken Huhne's points. It was untrue and was not published. Pryce then told the Sunday Times political editor Isabel Oakeshott that it was she who had taken his points, though she was not named as the recipient in Oakeshott's article.

Pryce claimed she was pressured by Huhne into signing a form saying she was the driver of his black BMW, with its personalised H11HNE plates, when it was clocked speeding on the M11 on 12 March 2003 as he returned home from Stansted airport after a session at the European parliament in Strasbourg.

She said she had resisted but had been "worn down" by Huhne constantly pressuring her to take the points because he already had nine on his licence and faced disqualification. He was seeking the Lib Dem nomination for Eastleigh at the time and told her it would be her fault if he did not get it, and his political career and image would be ruined, she said.

Pryce told the jury she was presented with a fait accompli after Huhne notified the authorities she was the driver. He forced her to sign, standing "pen in hand" next to her before she did so.

Pryce, a mother of five, described Huhne as "very driven" and "very ambitious" and said he could be arrogant. She told the jury he had twice tried to pressure her into having an abortion because the accidental pregnancies were "bad timing". She said she had a termination on the first occasion, which she had "regretted ever since", but resisted at the last minute on the second and went on to have their youngest child.